As the marine energy industry explores the potential for generating significant power from waves and tidal currents, there is a need to ensure that energy converters do not cause harm to the marine environment, including marine animals that may interact with these new technologies in their native habitats. The challenge of deploying, operating, and maintaining marine energy converters in the ocean is coupled with the difficulty of monitoring for potentially deleterious outcomes between the converters, anchors, mooring lines, power cables and other gear, and marine mammals, sea turtles, fish, and seabirds. To better understand the state of instrumentation and capabilities for monitoring around marine energy converters, the U.S. Department of Energy directed Pacific Northwest National Laboratory and the Northwest National Marine Renewable Energy Center at the University of Washington to convene an invitation-only workshop of experts from around the world to address instrumentation needs for three key interactions of interest to the emerging industry:
- interactions between marine animals and marine renewable energy converters (MECs) near the converters (“nearfield”)
- determining the distribution and habitat use of marine animals in the vicinity of MECs (“distribution and habitat use”)
- characterizing the sounds produced by MECs (“sound”).
The workshop participants were also asked to determine the capabilities of the following three instrumentation categories as they apply to monitoring around MECs:
- active acoustic instruments, including echosounders, imaging sonars, active tags, and radar
- passive acoustic instruments, including hydrophones and vector sensors
- optical technologies, focused on various camera deployment platforms.
Thirty-six scientists, engineers, and regulators from the United States, Canada, Europe, and Chile participated in the 2-day workshop, through a series of plenary presentations about the following:
- status of monitoring around MECs: purpose of monitoring, examples of success and limitations
- understanding the challenges of determining the distribution and habitat use of animals in the vicinity of MECs
- observing the effects of underwater sound on marine animals, and the regulatory context that drives these observations.
The bulk of the workshop was spent in breakout sessions that addressed the capabilities of the instrument systems of interest and the three situations around marine energy devices, where significant instrument needs, gaps, and solutions were identified (nearfield, distribution and habitat use, and sound).
For active acoustic instruments the discussion focused on the spatial and temporal limitations; data bandwidth and power requirements; data processing; seasonal, biological, atmospheric, environmental limitations; safety and permitting challenges; and mooring and platform challenges.
Passive acoustic instrument discussions included the capabilities of hydrophones and vector sensors; the challenges of data collection in extreme energy environments; and data processing resulting from monitoring. Optical technology discussions explored a range of deployment and data-gathering options including: underwater, surface, and airborne platforms.
The nearfield discussions stressed the importance of tailoring the monitoring around marine energy converters to the specific animals present at marine renewable energy sites, the animal life stages, and the protected status of the animals. The spatial scales over which each animal group ought to be monitored differs depending on the size and speed of the animal. While continuous temporal observations of converters is desirable, significant concern was expressed about the large data streams likely to be generated and the need for signal processing and software improvements in detection, tracking, localization, and classification of animals to enable automated data processing.
The distribution and habitat use group focused on the need to develop monitoring strategies for specific animal groups of interest that are peculiar to the high-energy areas in which marine energy converters are placed. The group focused on packages of instruments that could observe marine animals on temporal scales of months to years in order to understand how the presence of marine energy converters may alter animal use and behavior in their vicinity.
The sound group focused on how to measure sound from marine energy converters, how to determine if the measurements can adequately characterize the output of the converters, and how sound measurement techniques could be standardized.
Common themes that emerged from the aggregation of the breakout groups, informed by the plenary presentations and discussions, included the following:
- the importance of measuring risk as a key part of the initial plans for monitoring in order to focus programs appropriately, and to inform discussions that allow certain risks to be “retired” on a project-specific basis
- the potential for huge data “mortgages” resulting from large streams of data that will flow from many of the instruments best suited for monitoring, and the need for automated data processing to optimize the data streams
- the need to integrate instruments into packages that can be deployed and operated as a single unit, and the need to integrate monitoring data streams with those generated from converter operation
- the lack of existing platforms and supporting technologies to allow otherwise capable monitoring instruments to realize their potential
- the importance of broad collaboration among the research community internationally, between researchers and developers, as well as between researchers and regulators to cost-effectively and efficiently use limited monitoring funds to understand interactions of marine energy converters with marine animals.
More details on the workshop are available here.
A webinar was also held to summarize findings.